Werren, J.H.: Evolution and Consequences of Wolbachia Symbioses in Invertebrates

Wolbachia are a widespread group of bacteria that commonly found in insects, isopods, arachnids and nematodes. These cytoplasmically inherited bacteria cause a number of alterations in host reproduction, including induction of sperm-egg incompatibility, parthenogenesis, feminization of geneetic males, and male-killing. These alterations enhance transmission of the bacteria within host populations. Wolbachia may also have evolved mutualistic interactions with hosts. These bacteria are capable of moving between distantly related host taxa by mechanisms that are as yet unclear. It has been proposed that these bacteria may play a role in rapid speciation in invertebrates; however, this view is controversial. Information is presented on the evolutionary biology of these fascinating bacteria. In addition, theoretical and empirical studies relating to the possible role or Wolbachia in host speciation is discussed.